Closure for jars and the like



May 25, 1943- L. T. CRABBE CLOSURE FOR JARS AND THE LIKE Filed Feb. 15. 1941 Patented May 25, 1943 CLOSURE FOR JARS AND THE LIKE Lindsay Thorne Crabbe, Chicago, Ill., assignmto Phoenix Metal Cap Co. Inc., Chicago, 111., a corporation of New York Application February 15, 1941, Serial No. 319,141

lclaim;

The invention relates to new and useful improvements in a closure for jars and the like, and more particularly to a closure of the type wherein a sealing disk is held in sealing engagement with the jar lip by a metal cap having a. detachable connection with the jar.

An object of the invention is to provide a jar cap and sealing disk of the above type which are so constructed that the cap normally holds the sealing disk in contact with the sealing lip all the way across the same, and-wherein said sealing disk is permitted, under excessive internal gas pressure, to flex outwardly away from the sealing lip and thus reduce the seal between the disk and the jar lip to substantially a line contact to facilitate venting.

lrrthe drawing which shows by way of illustration one embodiment of the invention- Figure l is an enlarged sectional view showing a jar cap and a sealing disk embodying the invention prior to the attachment of the cap to the jar;

Fig. 2 is a view showing the cap attached to the jar and the sealing disk held in normal sealing engagement with the jar lip, and

Fig. 3 is a view similar to Figure 2, but showing the effect of excessive internal gas pressure on the sealing disk.

The present invention has to do with a jar closure which includes a sealing disk extending across the mouth of the jar and overlying the sealing lip thereof, and a metal cap which holds the seg disk in sealing contact with the jar. The closure cap is preferably made of metal and is provided with a depending skirt and a domeshaped top portion which extends all the way across from one side of the skirt to the other. The skirt is provided with any suitable means for securing the same to the jar. The sealing disk which is placed in the cap may be made of any suitable gasket material, and is so dimensioned that it extends all theway across the mouth of the jar and overlies the sealing lip thereof. This sealing disk before it is placed in the cap is die-shaped so that it curves away from the dome-shaped portion of the cap When the cap is applied, the sealing disk will contact with the lip all the way across so as to make a very eiilcient seal for the jar. The top of the cap being dome-shaped, curves outwardly away from the inner portion of the sealing lip of the jar and contacts solely with the sealing disk in the region directly over the outer portion of the lip. I If gas evolves from the contents of the Jar so as to produce an excessive pressure, the sealing disk will be caused to flex outwardly into contact with the dome of the cap, and this will separate the sealing disk from the inner portion of the lip, and reduce the seal between the disk and the lip to a substantial line contact adjacent the outer portion of the sealing lip. This will permit the gases to wedge in between the sealing lip and the sealing disk and force an escape through the line contact between the sealing disk and the lip, notwithstanding that the contact is a complete circumferential linecontact. 1

Referring more in detail to the drawing, the jar closure includes a metal cap having a depending skirt I and a top portion 2 which is dome-shaped, said dome extending all the way from one side of the skirt to the other. The depending shirt I i rolled inward so as to form a strengthening head 3, and the lower portion of the shrt is shaped as shown in the illustrated embodiment of the invention so as to provide a thread i which is adapted to engage threads 5 on the neck a of the jar for securing the cap to the jar.

Located within the metal cap is a sealing disk i which may be made of any suitable gasket material, and the sealing disk may be provided with any suitable protective coating on the inner face thereof as indicated at 8. This sealing disk before it is placed in the cap is die-shaped so as to give a convex shape to the disk. The sealing disk thus shaped is placed in the cap and will b retained therein in the usual manner. a

The container may be of any desired construction and is referred to as a jar without any thought of limiting the invention in its use. Whatever the container may be, it is provided with a neck portion to which a cap may be attached. Surrounding the mouth of the Jar is a sealing lip 9.. When the closure cap is applied to the jar, the sealing disk i extends across the mouth of the jar and overlies the sealing lip,

contacting therewith all the way across the same; as shown in Figure 2. The top portion 2 of the cap is dome-shaped as above noted, and the dome is unusually high so that the portions thereof indicated at 2" which are directly above the sealing lip, curve outwardly away from the sealing lip. As a result, when the cap is screwed on to the jar, this top portion 2 will contact with the sealing disk and press it firmly against the sealing lip. The pressure exerted against the sealing disk by the cap is in the region directly over the outer portion of the sealing lip, but this will force the sealing disk which normally curves inwardly into the mouth of the jar, firmly against the sealing lip of the jar all the way across the same.

Let us assume that the contents of the jar evolves'a gas, and thatthe pressure of the gas becomes excessive, so that the jar is likely to be disrupted. This gas pressure against the inher face of the sealing disk will flex: said sealing disk outward, forcing it into contact with the inner face of the dome of the cap disk, as noted above, is normally curved downwardly away from the top oi the cap, and therefore, it will curve into the mouth of the jar to a slight extent. This die-shaping of the disk stretches the disk so that it can hear from this inwardly curved position to the outwardlycurved position against the dome of the can under the pressure of the gases. When the disk is forced to the position shown in Figure 3, by the excessive pressure of the gases within the jar, the dish is moved away from the inner portion of the sealing lip and this reduces the seal to more or less or a line the jar so as to prevent disrupting the same, the

seal-is maintained against any possible entrance of air into the jar.

Whilethe cap is secured to the jar by a thread as illustrated, it will be understood that it may be secured in any desired .way whereby the cap may be drawn into tight sealing engagement with the jar. While the cap is described as made-of metal, it may be made oi any suitable material, and minor changes in the details of construction and the shaping of the parts may be made without departing frorn the spirit of the invention as set forth in the appended claim.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

A closure for containers comprising a cap having a depending skirt adapted to be secured to the container and including a substantially rigid top portion, the inner diameter oi the skirt portion of the cap being greater than the outer diameter of the sealing lip of the container, a sealing disk disposed within the cap and extending across the mouth of the container and contacting with the depending skirt of the cap so that said sealing dish overlies and extends beyond the sealing lip oi the container, said top portion of the cap being domed outwardly from the top of the skirt at one side thereof to the other so as to contact with the said sealing disk only directly over the outer edge of the sealing lip, said sealing disir being preformed so as to initially curve inwardly away from the inner surface of the dome-shaped top and into contact with the entire sealing surface of the sealing lip, said sealing disk'being adapted to flex outwardly under excessive internal gas pressure and move out of contact with the inner surface of the sealing lip of the container so as to reduce the sealing area between the disk and the sealing lip to substantially line contact at the outer edge of the sealing lip.

L SAY THORNE CRABBE. 

